The present invention relates to providing light of a selectable color using LEDs. More particularly, the present invention is a method and apparatus for providing multicolored illumination More particularly still, the present invention is an apparatus for providing a computer controlled multicolored illumination network capable of high performance and rapid color selection and change.
It is well known that combining the projected light of one color with the projected light of another color will result in the creation of a third color. It is also well known that the three most commonly used primary colorsxe2x80x94red, blue and greenxe2x80x94can be combined in different proportions to generate almost any color in the visible spectrum. The present invention takes advantage of these effects by combining the projected light from at least two light emitting diodes (LEDs) of different primary colors.
Computer lighting networks are not new. U.S. Pat. No. 5,420,482, issued to Phares, describes one such network that uses different colored LEDs to generate a selectable color. Phares is primarily for use as a display apparatus. However, the apparatus has several disadvantages and limitations. First, each of the three color LEDs in Phares is powered through a transistor biasing scheme in which the transistor base is coupled to a respective latch register through biasing resistors. The three latches are all simultaneously connected to the same data lines on the data bus. This means it is impossible in Phares to change all three LED transistor biases independently and simultaneously. Also, biasing of the transistors is inefficient because power delivered to the LEDs is smaller than that dissipated in the biasing network. This makes the device poorly suited for efficient illumination applications. The transistor biasing used by Phares also makes it difficult, if not impossible, to interchange groups of LEDs having different power ratings, and hence different intensity levels.
U.S. Pat. No. 4,845,481, issued to Havel, is directed to a multicolored display device. Havel addresses some, but not all of the switching problems associated with Phares. Havel uses a pulse width modulated signal to provide current to respective LEDs at a particular duty cycle. However, no provision is made for precise and rapid control over the colors emitted. As a stand alone unit, the apparatus in Havel suggests away from network lighting, and therefore lacks any teaching as to how to implement a pulse width modulated computer lighting network. Further, Havel does not appreciate the use of LEDs beyond mere displays, such as for illumination.
U.S. Pat. No. 5,184,114, issued to Brown, shows an LED display system. But Brown lacks any suggestion to use LEDs for illumination, or to use LEDs in a configurable computer network environment. U.S. Pat. No. 5,134,387, issued to Smith et al., directed to an LED matrix display, contains similar problems. Its rudimentary current control scheme severely limits the possible range of colors that can be displayed.
It is an object of the present invention to overcome the limitations of the prior art by providing a high performance computer controlled multicolored LED lighting network.
It is a further object of the present invention to provide a unique LED lighting network structure capable of both a linear chain of nodes and a binary tree configuration.
It is still another object of the present invention to provide a unique heat-dissipating housing to contain the lighting units of the lighting network.
It is yet another object of the present invention to provide a current regulated LED lighting apparatus, wherein the apparatus contains lighting modules each having its own maximum current rating and each conveniently interchangeable with one another.
It is a still further object of the present invention to provide a unique computer current-controlled LED lighting assembly for use as a general illumination device capable of emitting multiple colors in a continuously programmable 24-bit spectrum.
It is yet a still further object of the present invention to provide a unique flashlight, inclinometer, thermometer, general environmental indicator and lightbulb, all utilizing the general computer current-control principles of the present invention.
Other objects of the present invention will be apparent from the detailed description below.
In brief, the invention herein comprises a pulse width modulated current control for an LED lighting assembly, where each current-controlled unit is uniquely addressable and capable of receiving illumination color information on a computer lighting network. In a further embodiment, the invention includes a binary tree network configuration of lighting units (nodes). In another embodiment, the present invention comprises a heat dissipating housing, made out of a heat-conductive material, for housing the lighting assembly. The heat dissipating housing contains two stacked circuit boards holding respectively the power module and the light module. The light module is adapted to be conveniently interchanged with other light modules having programmable current, and hence maximum light intensity, ratings. Other embodiments of the present invention involve novel applications for the general principles described herein.